We propose to evaluate whether periodontitis is a risk factor for adverse pregnancy outcomes. The published studies evaluating these associations are few, small, mostly retrospective and show inconsistent results; although relative risks as high as 7.5 have been reported. We plan to add an oral component to the ongoing Project Viva, a prospective study of 6,000 pregnant women, to evaluate this association. Maternal infection during pregnancy has been demonstrated to play an important role in etiology of preterm delivery. Periodontal infection can serve as a reservoir of gram negative anaerobic organisms and their products, and proinflammatory mediators which could target the placental membranes via systemic circulation thus leading to preterm delivery or fetal growth restriction. The primary aim of this study is to examine the effect of maternal periodontitis on length of gestation and fetal growth. The secondary aim is to explore the association between periodontitis and serum levels of TNF-alpha. The proposed prospective nested case-control study will request pre-existing radiographs from Viva participants. Cases will be mothers who give birth to a preterm infant and mothers who give birth to a restricted fetal growth infant. Controls will be mothers with normal pregnancy outcome. We will enroll all cases and a random sample of controls in a 1:3 ratio, frequency matched by race, age and smoking status. Periodontal bone loss as a result of chronic periodontitis will be evaluated from the pre-existing radiographs. Viva participants who report having x-rays taken within last 5 years will be requested on the supplemental questionnaire after delivery to provide their existing dental radiographs or the name and address of the dentist who has these. We will then request the participants' dentists to provide existing bitewing radiographs. The radiographs will be interpreted by one well-calibrated dentist by using a visual categorization method. We will employ multivariate analyses to adjust for potential confounders. In addition, we will perform the analysis of TNF-alpha using blood samples that were pre-collected at first prenatal visit in Project Viva's pilot study (Pregval Study) to evaluate one potential pathway relating periodontitis and adverse pregnancy outcomes. The proposed study will help us clarify the relationships between periodontal disease and adverse pregnancy outcomes. Since periodontal disease is a highly prevalent condition that can be controlled, understanding these relationships is of significant importance, both for individuals and for public health policy aiming to improve the well-being of mothers and infants.